Dengue Linked to High Temperatures, El Nino, Global Warming

Fogging to prevent dengue and other diseases with mosquitoes as transmitting agent. Provincial Health Office of Bali regularly conducts fogging for the capital of the province, Denpasar. 18/06/2011. WHO/Budi Chandra.

Epidemics of dengue are linked to high temperatures brought by the El Niño weather phenomenon, a University of Florida scientist working with an international team of researchers has found, which in turn links it to the emerging threat of global warming.

The findings coincide with the emergence of the most intense El Niño in nearly two decades in the Pacific, raising the concern that a major increase in dengue cases will occur throughout Southeast Asian countries early next year.

UF biology professor Derek Cummings and his team found that an increase in dengue incidence swept through eight countries of Southeast Asia in 1997 and 1998 during a historically intense El Niño weather event.

“During years of large incidence, the number of people requiring hospitalization and care can overwhelm health systems. If we can understand the factors that contribute to these increases, we can prepare for them and act to mitigate the impact of the disease,” said Cummings.

The dengue virus is transmitted by mosquitoes in the tropics and subtropics, affecting an estimated 390 million a year globally. Though there is no specific pharmaceutical treatment, supportive therapy can greatly improve outcomes. A number of vaccine candidates are in development stage but none are currently licensed.

In addition, the study also found that urban areas act as dengue epidemic “pacemakers,” giving rise to traveling waves of large epidemics moving to nearby rural areas, as found across Southeast Asia.

The international study team involved scientists from 18 institutions around the world and the results of the study appear in the Proceedings of the National Academy of Sciences.